What Our Gearhead(R) Experts Are Saying: "I recommend this device anytime there's a big size difference between climber and belayer. It only engages when it needs to, so normal rope handling feels smooth, and catches stay soft instead of jarring. Boost Mode is especially useful when the difference is really noticeable." We've all been there-climbing partners with very different weights, sketchy first bolts, and the need for a little extra margin without sacrificing smooth belay technique. The Mammut Assist Belay Resistor is built to solve exactly that problem, adding friction only when it's actually needed. By attaching directly to the first quickdraw, it increases control during falls and lowering without fully locking the rope. The patented cam design activates only under load, allowing for dynamic belaying and soft catches while still helping lighter belayers manage heavier lead climbers. Boost Mode adds even more versatility by allowing faster engagement when weight differences are significant or when only the first bolt is clipped. Easy to release and intuitive to use, the Assist Belay Resistor adds confidence at the sharp end while preserving proper belay feel.